1. Field of the Invention
The present invention relates to an optical transmission apparatus.
2. Description of Related Art
Japanese Patent Laid-Open No. 2006-59883 discloses a conventional large-scale integrated circuit (LSI) package with an interface module. FIG. 1 is a diagram for illustrating a process of manufacturing the conventional LSI package with an interface module. The LSI package with an interface module has a signal processing LSI 102. The signal processing LSI 102 is mounted on an interposer 103, and the signal processing LSI 102 and the interposer 103 are electrically connected to each other.
High speed signal wiring 104 provided on the interposer 103 is electrically connected to a signal input/output terminal of the signal processing LSI 102 at one end. The other end of the high speed signal wiring 104 is drawn on the top surface of the interposer 103. Connection terminals 105 used for power supply or input/output of a low speed control signal are disposed on the bottom surface of the interposer 103. The connection terminals 105 are electrically connected to a mounting board 106.
An optical interface module 107 has an interface integrated circuit (IC), an optical element, an optical fiber 108 for high speed signal transmission, an optical coupling system for the optical fiber 108 and the optical element, and a flexible wiring board 109 and is mounted on a stiffener 110, which serves as a supporting substrate. The optical interface module 107 has two types of input/output parts. One of the input/output parts is an input/output pin 112, which is disposed at a position close to the mounting board 106 and is used for transmission of a low speed control signal or power supply signal. The input/output pin 112 is connected to a socket 113 mounted on the mounting board 106. The other input/output part is an electrical connection part 114, which electrically connects the optical interface module 107 and the high speed signal wiring 104 to each other and is used for high speed signal transmission. The electrical connection part 114 is spaced apart from the high speed signal wiring 104 by a predetermined distance by a protrusion 115. The electrical connection part 114 is inductively or capacitively coupled to the high speed signal wiring 104.
A process of manufacturing the LSI package with an interface module will be described. First, the interposer 103 with the signal processing LSI 102 mounted thereon is electrically connected to the mounting board 106 with the connection terminals 105. At the same time, the socket 113 and other components are mounted on the mounting board 106. Then, an electrode of the high speed signal wiring 104 and an electrode of the electrical connection part 114 are aligned with each other. Then, the input/output pin 112 is fitted into the socket 113, and at the same time, the optical interface module 107 and the high speed signal wiring 104 are electrically connected to each other with the electrical connection part 114.
The inventor has recognized the following problem with the conventional LSI package with an interface module. That is, the LSI package with an interface module is expensive because the interposer 103 is necessary to connect the optical interface module 107 to the signal processing LSI 102 and the socket 113 is necessary to transmit the power supply signal.